Data filtering is performed for datagram streams in cable service provider industry applications such as an OpenCable set-top-box (STB). OpenCable is an initiative managed by CableLabs with the goal of helping the cable industry deploy interactive services. In such applications, a Cable Headend continuously transmits a large amount of network traffic down in the DOCSIS Set-top Gateway (DSG) tunnel (a broadcast IP datagram stream originating at a DOCSIS Set-top Gateway at the Cable Headend and carrying Out-Of-Band messages intended for set-top terminals).
As such, Conditional Access Software is required to filter out the entitlement data packets with data pattern specified by a Conditional Access Client, and forward the data packets to the Client. However, conventional Conditional Access Software is not capable of understanding either the data format of incoming packets, or the format of mask/value patterns therein. As such, conventional Conditional Access Software indiscriminately and inefficiently processes incoming packets. There is a need for such Conditional Access Software to effectively and efficiently examine incoming data packets from a DSG tunnel and find the matching packets.